Attack on the uncastled king: pawn to c5 (c4·2)
c9-07515naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
An opening trap from this Chess960 starting position.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1110 ShuffleRating — club-player level.
White to move — find the best continuation
How to recognize this tactic
In Chess960 the pieces start on unfamiliar squares, so tactics appear earlier and from unusual angles. Do not trust classical patterns — read the actual lines of the bishops, the rooks and the queen from where they really stand in this position.
Early Chess960 traps punish natural but careless development. Look for a forcing move that exploits a piece the opponent has just placed on a poor square — a fork, a pin or a threat that wins material before either side is fully developed.
An uncastled king in the centre is a standing target. Look for ways to open the central files and diagonals against it with checks and threats before it can shelter — every tempo the king spends in the middle is a chance for a combination.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
General method: before you move, list the forcing candidates — every check, every capture, every direct threat — and calculate those first. The solution to a tactic is almost always among them.
Position on the board
White: king f1, queen b7, rook c1 g1, bishop d1 e1, knight a1 b1, pawn a2 b2 d2 e2 f2 h2 c4 g4.
Black: king f8, queen h8, rook c8 g8, bishop d8 e8, knight b6 b8, pawn g5 h5 a7 c7 d7 e7 f7.
16 white and 15 black pieces are on the board; the puzzle position arises after move 4.
The position in numbers
White are ahead by 1 points of material (39 against 38; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on f8.
It is White to move on move 4, with 41 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
4. c5 Nd5 5. Qxd5
Why it works
- Great move! pawn to c5 keeps the pressure (+3.4).
- Spot on — queen to d5 (+3.4).
- You win a piece — the knight.
- If instead Nd5, then Qxd5 and you win the knight.
Move by move
- 4. c5 — pawn to c5
- Nd5 — knight to d5
- 5. Qxd5 — queen to d5 (capture)
Types in this puzzle
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
Uncastled king
The king lingered in the middle — punish the delay.
Punishing the uncastled king: your opponent delayed castling, and now his king is stuck on its starting square under fire. In Chess960 this is deadlier than in classical chess — the king may start in the center or near the edge, and the familiar defensive setups simply do not apply. The signs: the victim still holds castling rights, and the files toward his king are half-open. Open lines before the king manages to hide.
Early trap
In the first moves of a fresh setup a trap already snaps shut.
An early trap is a tactic that snaps shut within the first moves: an unfamiliar setup hides shots that classical openings never produce. Examine every starting position with fresh eyes — which pieces already aim at each other, what hangs after the first pawn moves. Moves that feel "safe" from classical habit can lose on the spot here. Chess960 has no opening theory; it has alertness from move one.
About this position
These pieces come from starting position #89.
SP-89 · BastionScout — King shifted to c or f, with a knight committed to the corner from move one.
The king starts on f1, the rooks on c1 and g1, the queen on h1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The second rank carries 2 pawns with no defender at all: a2, b2.
The setup belongs to the BastionScout family; read right to left it becomes position 873.
The engine's main line opens with b4.
Morozov Balance Index: 61 of 100 — class B — balanced. Engine evaluation of the starting position: +23 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #89Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 007 · SP-89
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